arranging files in a folder depends on either, name, date, type or criteria such as that.
if you insist in having pictures in a certain order than you need to rename them either numerically or alphabetically ie:
thispicture.jpg, thatpicture.jpg
to 1thispicture.jpg, 2thatpicture.jpg
or athispicture.jpg, bthatpicture.jpg.